Sampling bomb and method of sampling and analyzing a heat of unkilled steel

ABSTRACT

A novel method of sampling a heat of molten unkilled steel to produce a sound solidified test ingot of magnesium killed steel which is suitable for analysis. An improved sampling bomb is also provided for use in practicing the sampling method of the invention. It is necessary to take and analyze only one sample for all of the common elements normally contained in steel. The prior art method requires that at least two samples be taken, and that at least two analysis be made to obtain comparable results.

United States Patent Zickefoose et al. A

[54] SAMPLING BOMB AND METHOD OF SAMPLING AND ANALYZING A HEAT OF UNKILLED STEEL [72] Inventors: Rox L. Zickeioose, Weirton, W. Va.; Gerald G. Miller, Toronto, Ohio; James R. Judge, Weirton, W. Va.

[73] Assignee: National Steel Corporation [22] Filed! Sept. 29, 1970 21 Appl. No.: 76,447

[52] US. Cl. ..73/425.4 R, 73/DlG. 9

51 Int. Cl. ..G0ln 1/12 [58] Field of Search ..73/DlG. 9; '164/4 [56] References Cited UNITED STATES PATENTS Perbix ..73/DlG. 9

Lowderrnilk ..73/DIG. 9 Menzen ..75/58 Jackson ..73/DlG. 9

Primary Examiner-S. Clement Swisher Attorney-Shanley and ONeil [57] ABSTRACT A novel method of sampling a heat of molten unkilled steel to produce a sound solidified test ingot of magnesium killed steel which is suitable for analysis. An improved sampling bomb is also provided for use in practicing the sampling method of the invention. It is necessary to take and analyze only one sample for all of the common elements normally contained in steel. The prior art method requires that at least two samples be taken, and that at least two analysis be made to obtain comparable results.

20 Claims, 6 Drawing Figures PAIENTEDBEB 5 I912 3704521 ROX L. ZICKEFOOSE GERALD G. MILLER JAMES R. JUDGE BY $404111 M ATTORNEYS BACKGROUND OF THE INVENTION This invention broadly relates to a novel method of sampling a heat of molten unkilled steel to produce a sound solidified sample of killed steel which is suitable for analysis. In one of its more specific variants, the invention further relates to a novel method of analyzing a heat of molten unkilled steel by emission spectrochemical analysis to determine the concentrations of a plurality of substances. The invention further provides an improved sampling bomb which is especially useful in practicing the sampling method and the analytical method of the invention.

Emission spectrochemical analysis is widely used for analyzing steel. When using this method of analysis, it-is essential that the steel sample be fully killed, sound and free of cracks, voids, gas pockets and other imperfections. Otherwise, the analytical results are not reliable.

A number of prior art methods have been used heretofore for sampling molten unkilled steel to obtain test ingots of fully killed steel which are suitable for emission spectrochemical analysis. In accordance with one practice, .a sampling bomb having a cavity for receiving a molten steel sample and a deoxidizing agent therein is immersed in' the heat of unkilled steel. Aluminum and/or zirconium were usually used as the deoxidizers, and silicon was used in some instances. The unkilled steel is introduced into the cavity and. is killed by the deoxidizing agent, and the sampling bomb containing the resulting molten killed steel sample is removed from the heat. The sample is then solidified to produce a test ingot of fully killed steel for analysis.

Silicon is present in steel as a naturally occurring constituent, and aluminum and zirconium are often added to steel. As a result, a complete analysis of a steel sample usually includes an analysis for silicon, aluminum and zirconium. In instances where-these substances are used as a deoxidizing agent during the preparation of the steel sample, the presence of residual deoxidizing agent prevents reliable analytical data from being obtained. This problem has been overcome heretofore by obtaining and analyzing at least two steel samples. Aluminum is used to kill one sample and zirconium is used to kill the other. The analytical data from the aluminum killed sample are used to determine the zirconium content, and the analytical data from the zirconium killed sample are used to determine the aluminum content. Thus, it was necessary in accordance with the prior art practice to take at least two samples of the unkilled steel, use different deoxidizers, analyze two or more samples, and thereafter select data from at least two sets in order to obtain the complete analysis.

Magnesium was not used heretofore as a deoxidizing agent in sampling bombs as it was thought to be unsatisfactory. The prior art taught that metallic magnesium is extremely reactive at elevated temperature, and tends to react explosively with molten unkilled steel. It was thought that a violent reaction during deoxidation would 'not result in a killed steel sample suitable for emission spectrochemical analysis due to the presence of imperfections such as cracks, voids and gas pockets. It has been discovered unexpectedly that it is possible to use metallic magnesium as a deoxidizing agent in sampling bombs of the size employed in preparing test ingots for emission spectrochemical analysis. The test ingots weigh less than 10 pounds and preferably less than 5 pounds, and usually weigh from about 1 ounce to 4 pounds. For some reason which is not fully understood at the present time, the use of metallic magnesium to prepare test ingots of this size does not adversely affect thequality thereof for purposes of emission spectrochemical analysis. The quality actually seems to improve as the magnesium killed test ingots are sound and free of undesirable inculsions, cracks, voids and gas pockets, and give consistent analytical results.

Magnesium is not an addition agent for steel nor normally present as an essential constituent of steel. It is possible to take one sample and analyze the one sample for all of the common elements normally present including carbon, manganese, sulfur, phosphorus, silicon, tin, copper, chromium, nickel, molybdenum, aluminum, zirconium, vanadium, columbium, titanium, arsenic, boron, oxygen, hydrogen and nitrogen. The present invention reduces the cost of analyzing heats of steel to approximately one-half of that of the prior art. Inasmuch as numerous samples are taken daily in a steel making operation, the savings over a period of time are very substantial.

It is an object of the present invention to provide a novel method of sampling a heat of molten unkilled steel to produce a sound solidified test ingot of killed steel which is suitable for analysis.

It is a further object to provide a novel method of analyzing a heat of molten unkilled steel wherein a test ingot of killed steel is obtained therefrom by the sampling method of the invention, and the ingot is thereafter analyzed to determine the concentrations of a plurality of substances.

It is a further object to provide an improved sampling bomb which is especially useful in practicing the sampling method of the invention.

It is a further object to provide a method of sampling a heat of molten unkilled steel wherein a sample thereof is obtainedwith a sampling bomb which has a refractory construction, the sample is killed in the sampling bomb with metallic magnesium, and the resulting molten killed steel sample is solidified in the sampling bomb in the form of a test ingot which is suitable for emission spectrochemical analysis.

It is a further object to provide a novel method of analyzing a heat of molten unkilled steel wherein a test ingot of magnesium killed steel is produced in accordance with the sampling method of the invention, and the test ingot is thereafter analyzed by emission spectrochemical analysis to determine the concentra tions of a plurality of substances including silicon, aluminum and zirconium.

It is still a further object to provide a refractory sampling bomb which is especially useful in practicing the preferred sampling method of the invention, wherein metallic magnesium is used as a deoxidizing agent.

Still other objects and advantages of the invention will be apparent from the following detailed description of the invention and the examples.

3 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating one presently preferred embodiment of the sampling bomb of the invention; I

FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1, illustrating the use of a thin elongated strip-like body of metallic magnesium as a deoxidizing agent;

FIG. 3 is a cross-sectional view. similar to that of FIG. 2, but illustrating the use of metallic'magnesium inparticulate form as a deoxidizing agent;

FIG. 4 is a further cross-sectional view similar to FIG. 2, but illustrating the use of an ampulefilled with powdered magnesium as a deoxidizing agent;

FIG. 5 is a further cross-sectional view similar to FIG. 2, but illustrating the use of metallic magnesium in the fonn ,of a thin sheet-like body as a deoxidizing agent; and Q I FIG. 6 is a schematic cross-sectional view in elevation of a prior art metallurgical vessel having a slag covered heat of molten unkilled steel therein, illustrating the use of the sampling bomb of the invention to obtain a killed steel sample suitable for emission spectrochemical analysis.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING PREFERRED VARIANTS THEREOF Referring now to the drawings, the sampling bomb generally designated as 10 includes an upright steel tubular member 11 which is open at its upper end and is closed off at its lower end by steel chill plate 12. The tubular member 11 and chill plate 12 define a cavity 14 for receiving a sample of molten steel, which is introduced therein through the opening 15.

A steel tubular handle 16 is attached at its inner end to tubular member 11, and extends outward therefrom at a suitable angle to maintain the member 11 in an upright position when the sampling bomb 10 is immersed in a heat of steel to be sampled. The outer surfaces of tubular member 1 l, chill plate 12 and tubular handle 16 are coated with a layer of refractory material 17 such as fire clay. The opening is sealed off by closure 18 which is adhes'ively attached along its marginal edge 19 to the refractory material 17. The closure 18 is constructed of a material which melts, decomposes or otherwise disintegrates when the sampling bomb 10 is immersed in a heat of molten unkilled steel, thereby rendering the closure 18 ineffective to seal off the opening 15 and allowing a sample of molten unkilled steel to be introduced into cavity 14. Examples of suitable materials for use in constructing closure 18 include metallic materials such as sheet steel and aluminum, and heat resistant paper which is preferably multilayered and sufficiently thick to withstand the temperature of the heat of steel for a period of time sufficient to allow the sampling bomb 10 to be immersed to the position illustrated in FIG. 6 of the drawings.

As is best seen in FIG. 6, the steel handle 16 and the refractory layer 17 thereon are sufficiently long to remain above the slag layer 20 when the sampling bomb 10 is immersed to a depth suitable for taking a sample of the heat of unkilled steel 21. A rod-like steel handle 23 is inserted into the outer end of tubular handle l6,and extends outward therefrom through opening 24 a distance suitable for allowing the sampling bomb 10 to be immersed within the heat of unkilled steel 21 by a workman.

The sampling bomb 10 has a deoxidizing agent 25 in the cavity 14 which consists essentially of metallic magnesium. The deoxidizing agent 25 may be present in a number of widely differing forms of metallic magnesium, several of which are illustrated in FIGS. 2 through 5. With reference to FIG. 2, the metallic magnesium is a thin elongated strip-like body 26 such as wire, strip, or tumings. In FIG. 3 of the drawings, the metallic magnesium is in the form of particles 27 such as granules, flakes, or powder. In FIG. 4 of thedrawings, anelongated ampule 28 contains the metallic magnesium in a finely divided form such as granules, flakes, orpowder.

Preferably, the ampule 28 extends from the chill plate 12 upward through cavity 14 to a short distance below the openinglS. With reference to FIG. 5, the metallic magnesium is in the form of a thin sheet-like body 29 such as foil or a thin layer or coating of metallic magnes ium that is deposited electrolytically or by other means on the internal surface of tubular member 11 and/or chill plate 12. If desired, magnesium foil may be shaped to conform with the internal surfaces of tubular member 11 and/or chill plate 12.

The metallic magnesium 25 is present within cavity 14 in an amount sufiicient to deoxidize the sample of molten unkilled steel which is introduced therein. As a general rule, the molten unkilled' steel sample introduced into cavity 14 should be intimately contacted with about 0.01-1 percent by weight of metallic magnesium, and preferably with about'0.050.5 percent by weight. Usually the present invention is'more effective at oxygen levels of 250 parts per million and less, but higher oxygen levels may be present. The amount of metallic magnesium to be used in a given instance to achievethe best results will depend upon the oxygen level in the steel sample. For the best results, about 0.1 percent by weight of metallic magnesium should be used for each parts per million of oxygen in the unkilled steel sample. For instance, when the unkilled steel sample contains 150 parts per million of oxygen, then about 0.1 percent of metallic magnesium may be intimately contacted therewith. At high oxygen levels of 300, 450, 600 and 750 parts per million, the molten unkilled steel sample may be intimately contacted with about 0.2%, 0.3%, 0.4% and 0.5% by weight of metallic magnesium, respectively, to achieve the best results. It is understood that the molten steel sample is contacted with sufficient metallic magnesium to produce a solidified test ingot which is properly killed. When the metallic magnesium is present in the quantities set out herein, a properly killed test ingot is produced which is solid and homogeneous, and upon metallurgically polishing, no pin holes, inclusions and other imperfections are visible to the unaided eye.

FIG. 6 of the drawings illustrates the use of the sampling bomb 10 of the invention to obtain a sample of the heat of molten unkilled steel 21 contained in metallurgical vessel 22. A molten protective slag layer 20 is tory layer 17 are sufficiently long so that the outer ends extend above the level of the slag layer 20, thereby assuring that the steel handle 23 remains intact.

Upon immersing the sampling bomb to the position illustrated in FIG. 6 of the drawings, the closure 18 disintegrates under the temperature conditions existing within the heat of unkilled steel 21, thereby rendering the closure 18 ineffective for sealing off the opening 15. The molten unkilled steel 21 then flows through opening into the cavity 14 and fills. the same. The molten unkilled steel in cavity 14 is intimately contacted with the deoxidizing agent 25, and a molten killed steel sample is produced. The sampling bomb 10 is withdrawn from the heat of molten steel 21, and from vessel 22, and the molten killed steel contained in bomb 10 is solidified to produce a test ingot suitable for prior art analysis, such as by wet, colorimetric or emission spectrochemical analysis.

The heat of molten unkilled steel to be sampled in accordance with the present invention may be prepared, for example, in an open hearth, a BOF furnace, or an electric furnace by prior art processes. The sampling bomb and method may be used to sample substantially any type of molten unkilled steel that is produced commercially. The unkilled steel usually contains less than 0.5 percent carbon, and in most instances about 0.0l-0.30 percent carbon. The oxygen content of the unkilled steel will vary inversely with the carbon content, and may extend from approximately 1,000 parts per million at the lower end of the carbon range to approximately 50 parts per million of oxygen at the higher end of the carbon range. The present invention produces better results when the unkilled steel contains less than 250 parts per million of oxygen.

The metallic magnesium may be present in substantially pure form or as an alloy. In instances where a magnesium alloy is'employed, then the remaining constituents should be substances which are not to be determined analytically in the steel. Thus, the solidified test ingot may be analyzed for all of the common elements which are normally present in steel, including carbon, manganese, sulfur, phosphorus, silicon, tin, copper, chromium, nickel, molybdenum, aluminum, zirconium, vanadium, columbium, titanium, arsenic, boron, nitrogen, hydrogen and oxygen.

Metallic magnesium may be used as a deoxidizing agent in any suitable prior art apparatus for obtaining an unkilled molten steel sample which does not exceed a few pounds in weight. The solidified test ingots should not exceed about 10 pounds in weight, and preferably not more than about 4 to 5 pounds in weight. The invention is especially useful in obtaining steel samples varying in weight from about I ounce to 4 pounds, and having a size and shape convenient for use in emission spectrochemical analysis. Metallic magnesium is especially useful in killing steel samples obtained from a basic oxygen furnace when using immersion sampling bombs or probes of the type illustrated in US. Pats. Nos. 3,298,069 and 3,494,200.

The solidified test ingots prepared in accordance with the present invention are analyzed by prior art techniques preferably employing the principles of emission spectrochemical analysis. One suitable analytical technique of this type, including the apparatus to be employed therein, is described by Andermann in an article entitled Suggested Method for spectrochemical Analysis of Carbon and Low Alloy Steels by the Condensed Arc Technique Using a Recording Photoelectrical Vacuum Spectrometer. This article is further identified as proposed ASTM method No. E-2 SM 9-22, and it appears on pages 639-645 of the'text ASTM Methods for Emission Spectrochemical Analysis (1954) 4th Edition. The teachings of this text, including the Andermann article, are incorporated herein by reference. Other suitable analytical techniques may be employed when desired.

A steel sample is unsatisfactory for. purposes of em is sion spectrochemical analysis when it has visible cracks, voids, blow holes or pin holes, or when it has undesirable impurities entrapped therein such as slag or slag-like materials. The voids, blow holes or pin holes are often formed in the steel as it solidifies due to the steel not being fully killed. The present invention overcomes this source of imperfections by providing sufficient metallic magnesium to assure that the test ingot is fully killed prior to solidification. Mechanical entrapment of gases also presents a problem in sampling bombs of the type illustrated in the drawings. The molten steel rushes into the cavity and the gases initially filling the cavity are entrapped. The only way the entrapped gases can escape is by bubbling up through the molten steel. If the molten steel is solidified before the gases escape, or if the gases do not escape completely, then voids are formed in the steel re gardless of whether or not it is fully killed. Slat or slaglike impurities may be entrapped in the steel in the same manner.

The use of metallic magnesium in the sampling bomb overcomes the above problems. The metallic magnesium has a relatively low melting point and boiling point, and it is believed that itmelts and vaporizes upon contacting the molten steel. It is also believed that metallic magnesium vapor then reacts immediately with the reactive constituents of the air initially present in the mold cavity, including the oxygen and nitrogen contents, to form non-gaseous inorganic substances which have a relatively small volume and low specific gravity. The inorganic substances are removed as a slag-like material which immediately floats to the top of the test ingot. The relatively small amount of entrapped inert gases such as argon do not present a problem as they are substantially insoluble in molten steel and pass immediately therefrom. The molten killed steel is free of entrapped gases, slag, and slag-like constituents, and it may be solidified to produce a sound test ingot for analysis.

The use of finely divided metallic magnesium markedly increases the rate of reaction between the reactive constituents of the entrapped air and/or the reactive constituents present in the steel including dissolved oxygen and/or nitrogen. It is usually preferred that the magnesium be in a finely subdivided form such as granules, flakes or powder, having a size of minus 5 mesh and for best results minus 30 mesh (Tyler screen). Thin foil or sheet which has an extensive surface area per unit weight of metallic magnesium produces comparable results and may be used. When the magnesium is present in these preferred forms,it is capable of being vaporized and reacting almost instantaneously with the reactive gaseous constituents problem.

present within cavity 14 and the oxygen in the molten steel. The use of a source of metallic magnesium which extends substantially from the opening 15 down to the chill plate 12 also aids in obtaining optimum results. As is well known, elemental magnesium reacts with explosive violence at elevated temperature in the presence of oxygen. Surprisingly, for some reason which is not fully understood at the present time, apparently the reaction within the cavity of the test mold occurs in such a manner that the usual detrimental effects of the explosive reaction are overcome.

The use of metallic magnesium as adeoxidant has still other advantages. For instance, the internal surface of steel tubular member 11 is protected from corrosion and remains bright and free of oxides and other corrosion products. The'corrosion products which normally form on unprotected steel surfaces have an adverse effect upon the test ingot, and this is prevented by using the highly reactive metallic magnesium as a deoxidizing agent. As a result, the sampling bombs of the present invention may be stored for long periods of time while awaiting use, and adverse storage conditions are not a It is understood that the term unkilled steel, as used herein inthe specification and claims, is intended to embrace partially killed steel and steel in general which has a dissolved oxygen content that is too high to produce a solidified test ingot suitable for emission spectrochemical analysis without adding a deoxidizing agent to the molten steel sample prior to-solidification.

The foregoing detailed description and the following specific examples are for purposes of illustration only.

EXAMPLE I A heat of low carbon steel is prepared by a basic oxygen process following prior art steel making practices, and the heat is tapped into a ladle. The steel has a temperature of about 2,940 F. and the oxygen content in the steel as tapped is about 400 parts perr nillion. Ladle additions of ferrosilicon andpig aluminum are made, and the oxygen content in the steel following the ladle additions is approximately 125 parts per million.

The refractory sampling bomb illustrated in FIG. 1 of the drawings is used to obtain-a sampleof the steel in the ladle following a technique similar to that illustrated in FIG. 6 of the drawings. The cavity in the sam- The test ingot is analyzed by emission spectrochemical analysis following the general procedure described by Andermann on pages 639-645 of the text ASTM Methods for Emission spectrochemical Analysis", (1954), 4th Edition, for the commonly occurring constituents in steel. The analysis indicates that the steel contains 0.087% carbon, 0.51% manganese, 0.035% sulfur, 0.010% phosphorus, 0.026% silicon, 0.017% copper, 0.018% chromium, 0.020% nickel, 0.01 1% molybdenum, 0.051% aluminum, 0.004% zirconium, 0.001% vanadium, 0.002% columbium, 0.005% titanium, 0.022% arsenic and 0.0003% boron. This analysis is confirmed by the analytical data of Example ll. Thus, it is necessary to take only one magnesium-killed sample and analyze the one sample to obtain the concentrations of all elements normally present in steel.

EXAMPLE 11 This example illustrates the prior art method of obtaining steel samples for analysis by emission spectrochemical analysis.

Two additional steel samples of the heat of Example I are obtained. The same sampling technique is used with the exception of omitting the magnesium deoxidizing agent of Example I, using zirconium as a deoxidizing agent for killing one sample, and using aluminum as a deoxidizing agent for killing the other sample. The remaining steps for producing the solidified test ingots are the same as in Example I.

The two test ingots are subjected to emission spectrochemical analysis following the technique of Example I. Whenthe zirconium killed test ingot is analyzed, the zirconium content of the steel is shown to be markedly higher than in the analysis for Example 1 due to the presence of residual zirconium from the deoxidizing agent. However, the analysis for the remaining elements are substantially the same as in Example 1.

pling bomb contains 1.5 grams of metallic magnesium in theform of a thin turning, and the cavity is of a size to produce a solidified test ingot weighing approximately 2 pounds. The closure for the opening leading to the cavity is constructed of multilayered heat resistant paper and has a thickness of approximately l/32 inch.

A protective layer of molten slag is maintained over the heat of steel in the ladle. The sampling bomb is quickly immersed through the slag layer and into the unkilled steel. The closure disintegrates within a few seconds, and the cavity is filled with the molten unkilled steel. The steel is killed by the magnesium turning in the cavity, and a molten killed steel sample is produced within the cavity.

The sampling bomb is then withdrawn from the heat of steel and the molten killed steel sample is allowed to solidify in the cavity. The solidified test ingot thus produced is removed from the sampling bomb, and is cooled sufficiently to allow handling.

When the aluminum killed test ingot is analyzed, the aluminum content is found to be markedly higher than in the analysis for Example 1 due to the presence of residual aluminum from the deoxidizing agent. However, the analysis for the remaining elements are substantially the same as in Example I.

From the above results, it is apparent that when the prior art aluminum and zirconium deoxidizing agents are employed, it is necessary to take at least two steel samples and make at least two analyses in order to obtain a complete set of analytical data.

We claim: l A method of sampling a heat of molten unkilled steel to produce a solidified test ingot of killed steel for analysis and analyzing the same comprising preparing a heat of molten unkilled steel, sampling said heat to obtain a sample of the molten unkilled steel, the sample of the molten unkilled steel not exceeding about ten pounds in weight,

intimately contacting the sample of molten unkilled steel with about 0.01-1 percent by weight of a deoxidizing agent consisting essentially of metallic magnesium,

the sample of molten unkilled steel being intimately contacted with the metallic magnesium in an amount to deoxidize the same and to produce a sample of molten killed steel,

solidifying the sample of molten killed steel in a test mold to produce a test ingot of killed steel suitable for analysis by emission spectrochemical analysis,

the sample of molten unkilled steel being isolated from the surrounding atmosphere while it is intimately contacted with the metallic magnesium to produce the sample of molten killed steel, and

analyzing at least a portion of the said'killed steel by emission spectrochemical analysis.

2. The method of claim 1 wherein the molten unkilled steel sample is from about 1 ounce to 4pounds in weight.

3. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.050.5 percent by weight of metallic magnesium.

4. The method of claim 1 wherein the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the test ingot is analyzed to determine the concentrations of silicon, aluminum and zirconium.

5. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with a thin elongated strip-like body of metallic magnesium.

6. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with a thin sheet-like body of metallic magnesium.

7. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with finely divided particles of metallic magnesium.

3. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05-0.5 percent by weight of a thin elongated striplike body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel thus produced is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.

9. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05-0.S percent by weight of a thin sheet-like body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.

10. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05O.5 percent by weight of finely divided particles of metallic magnesium, the finely divided particles of metallic magnesium are substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.

11. A method of analyzing a heat of molten unkilled steel comprising preparing a heat of molten unkilled steel,

immersing a sampling bomb having a cavity therein for receiving a sample of molten unkilled steel into said heat, the said cavity of the immersed sampling bomb being beneath the surface of said heat, introducing a sample of the molten unkilled steel into the said cavity of the immersed sampling bomb, the sample of molten unkilled steel in the said cavity not exceeding about ten pounds in weight, intimately contacting the sample of molten unkilled steel in said cavity of the immersed sampling bomb with about 0.01-1 percent by weight of a deoxidizing agent consisting essentially of metallic magnesium,

the sample of molten unkilled steel being intimately contacted with the metallic magnesium in an amount to deoxidize the same and to produce a sample of molten killed steel in said cavity of the immersed sampling bomb,

thereafter withdrawing the immersed sampling bomb and the sample of killed steel contained therein from said heat, solidifying the sample of molten killed steel in the sampling bomb to produce a solidified test ingot of killed steel suitable for analysis by emission spectrochemical analysis, and

analyzing at least a portion of said solidified test ingot of killed steel by emission spectrochemical analysis. i

12. The method of claim 11 wherein the molten unkilled steel sample in said cavity is from about 1 ounce to 4 pounds in weight.

13. The method of claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.050.5 percent by weight of metallic mag nesium.

lfl. The method of claim 11 wherein the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the test ingot is analyzed to determine the concentrations of silicon, aluminum and zirconium,

15. The method of claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with a thin elongated strip-like body of metallic magnesium.

l6 Tlgmethod of claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with a thin sheet-like body of metallic magnesium.

17. The method of claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with finely divided particles of metallic magnesium.

1 8. The method of claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.05O.5 percent by weight of a thin elongated strip-like body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.

19. The methodof claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.050.5 percent by weight of a thin sheetlike body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.

20. The method of claim 11 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.05O.5 percent by weight of finely divided particles of metallic magnesium, the finely divided particles of metallic magnesium are substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis. 

1. A method of sampling a heat of molten unkilled steel to produce a solidified test ingot of killed steel for analysis and analyzing the same comprising preparing a heat of molten unkilled steel, sampling said heat to obtain a sample of the molten unkilled steel, the sample of the molten unkilled steel not exceeding about ten pounds in weight, intimately contacting the sample of molten unkilled steel with about 0.01-1 percent by weight of a deoxidizing agent consisting essentially of metallic magnesium, the sample of molten unkilled steel being intimately contacted with the metallic magnesium in an amount to deoxidize the same and to produce a sample of molten killed steel, solidifying the sampLe of molten killed steel in a test mold to produce a test ingot of killed steel suitable for analysis by emission spectrochemical analysis, the sample of molten unkilled steel being isolated from the surrounding atmosphere while it is intimately contacted with the metallic magnesium to produce the sample of molten killed steel, and analyzing at least a portion of the said killed steel by emission spectrochemical analysis.
 2. The method of claim 1 wherein the molten unkilled steel sample is from about 1 ounce to 4 pounds in weight.
 3. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05-0.5 percent by weight of metallic magnesium.
 4. The method of claim 1 wherein the solidified test ingot is analyzed.
 5. The method of claim 1 wherein the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the test ingot is analyzed to determine the concentrations of silicon, aluminum and zirconium.
 6. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with a thin elongated strip-like body of metallic magnesium.
 7. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with a thin sheet-like body of metallic magnesium.
 8. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with finely divided particles of metallic magnesium.
 9. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05-0.5 percent by weight of a thin elongated strip-like body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel thus produced is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.
 10. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05-0.5 percent by weight of a thin sheet-like body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.
 11. The method of claim 1 wherein the molten unkilled steel sample is intimately contacted with about 0.05-0.5 percent by weight of finely divided particles of metallic magnesium, the finely divided particles of metallic magnesium are substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.
 12. A method of analyzing a heat of molten unkilled steel comprising preparing a heat of molten unkilled steel, immersing a sampling bomb having a cavity therein for receiving a sample of molten unkilled steel into said heat, the said cavity of the immersed sampling bomb being beneath the surface of said heat, introducing a sample of the molten unkilled steel into the said cavity of the immersed sampling bomb, the sample of molten unkilled steel in the said cavity not exceeding about ten pounds in weight, intimately contacting the sample of molten unkilled steel in said cavity of the immersed sampling bomb with about 0.01-1 percent by weight of a deoxidizing agent consisting essentially of metallic magnesium, the sample of molten unkilled steel being intimately contacted with the metallic magnesium in an amount to deoxidize the same and to produce a sample of molten killed steel in said cavity of the immersed sampling bomb, thereafter withdrawing the immersed sampling bomb and the sample of killed steel contained therein from said heat, solidifying the sample of molten killed steel in the sampling bomb to produce a solidified test ingot of killed steel suitable for analysis by emission spectrochemical analysiS, and analyzing at least a portion of said solidified test ingot of killed steel by emission spectrochemical analysis.
 13. The method of claim 12 wherein the molten unkilled steel sample in said cavity is from about 1 ounce to 4 pounds in weight.
 14. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.05-0.5 percent by weight of metallic magnesium.
 15. The method of claim 12 wherein the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the test ingot is analyzed to determine the concentrations of silicon, aluminum and zirconium.
 16. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with a thin elongated strip-like body of metallic magnesium.
 17. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with a thin sheet-like body of metallic magnesium.
 18. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with finely divided particles of metallic magnesium.
 19. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.05-0.5 percent by weight of a thin elongated strip-like body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.
 20. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.05-0.5 percent by weight of a thin sheet-like body of metallic magnesium, the metallic magnesium is substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis.
 21. The method of claim 12 wherein the molten unkilled steel sample is intimately contacted in said cavity with about 0.05-0.5 percent by weight of finely divided particles of metallic magnesium, the finely divided particles of metallic magnesium are substantially free of silicon, aluminum and zirconium, and the solidified test ingot of killed steel is analyzed for elements including silicon, aluminum and zirconium by emission spectrochemical analysis. 